There have been reports/complaints for years about "that tingling sensation" when a Mac laptop is connected to a wall outlet with a 2-prong plug.
Use Apple's 3-prong "extension" (that plugs into the charger block), and the tingling... disappears.
That's because the connection is now fully grounded (hot wire, neutral, ground).
Of course the 3-prong 110v plug is unique to the United States, Canada, perhaps Central/South America (I have no idea about south of the American border).
I don't know how Europeans (with their strange 220v 2-prong plugs) handle this...